@Ash Peng Thanks for reaching out. Azure offers different services with different workloads. You can always refer to the compute discission tree to validate which would be better service for your load/use case and how you want to migrate the service to cloud.
In short if you have event driven workload with short lived process then you can choose azure function as I am not sure for how long your individual thousand of services would run. You can create a Python function that runs your automated tests, and configure the function to be triggered by a timer or other event.
Other option could be Azure batch if you have HPC workload for your automation scripts that is compute intensive works.
If you want to migrate and change it to containerized service then you also review azure container apps.
I will suggest to review this document and then choose the right service for your workload.